RESUMEN
[Objective]To compare long-term conversion between fresh and cryopreserved osteochondral allografts in order to further provide theoretical foundation for treatment of articular cartilage defect using osteochondral allografts. [Methods]Articular cartilage defect models of 5 mm in diameter and depth were established for 32 New Zealand rabbit’s knees and treated by fresh and cryopreserved osteochondral allografts. Allografts were harvested and assessed by observing and analysing proteoglycan content,chondrocyte viability and ultrastructure of articular cartilage using Alcianblue staining and BCECF-AM /PI fluorescent staining,respectively,at 12 and 18 months postoperatively.[Results]Proteoglycan content and percentage of viable chondrocytes of osteochondral allografts were obviously decreased.Results of fresh osteochondral allografts were significantly better than those of cryopreserved osteochondral allografts at different time points. Ultrastructure of chondrocytes demonstrated degenerative changes.[Conclusion]In treatment of artificial articular cartilage defect ,serious degenerative changes were found for both fresh and cryopreserved osteochondral allografts at a long period,suggesting that fresh,especially cryopreserved osteochondral allografts are not feasible to treat articular cartilage defect.